Recently, a team led by Prof. Huang Qing at the Institute of Intelligent Machines, Hefei Institutes of Physical Science (HFIPS) of the Chinese Academy of Sciences (CAS) have reported the fabrication of ultrasensitive biosensors based on surface-enhanced Raman spectroscopy (SERS) to detect the cancer metastasis related programmed death ligand (PD-L1) biomarker. In this research, scientists fabricated highly sensitive and specific aptamer-functionalised probes based on Au/TiO2/Fe3O4 (shell/core) magnetic nanocomposites and Ag/4-ATP/Au (shell/core) SERS nanotags.
Using the “sandwich” approach, they captured the malignant exosomes between magnetic nanocomposites and SERS nanotags with which they could quantitatively measure the PD-L1 biomarker as low as 4.31 ag mL‒1 by analysing the Raman report signals.
In the mice model, the researchers confirmed that the proposed technique could be useful in analysing time dependent growth of tumours by analysing enhancement in PD-L1 expression in the tumour. Moreover, the researchers demonstrated the applicability of their work by integrating nanoparticles probes with a portable Raman spectrometer to realise the PD-L1 measurement with 95 % sensitivity.
Overall, the outcome of this work demonstrated the great clinical significance of PD-L1 biomarker diagnosis which in future would be helpful in monitoring patients’ health who undergo PD-L1/PD-1 immunotherapy.